1. Field of the Invention
The present invention relates to a fuel supply apparatus, through which fuel is supplied to a tank through a fuel path of a fuel inlet pipe.
2. Description of the Related Art
In a fuel supply apparatus, a fuel tank cap must be removed to supply fuel through the fuel inlet pipe. The fuel tank cap has a gasket pressed against an opening (filler neck) of the fuel inlet pipe, in order to prevent fuel vapor in the fuel tank from being released to the air. The fuel tank cap has the gasket mounted on an outer circumference of a cylindrical casing main body. The gasket receives a torsional force and is in close contact with the filler neck for sealing when the fuel tank cap is screwed in place within the inlet opening of the filler neck.
Conventional fuel supply apparatus exhibit poor operability in opening and closing the fuel tank cap. Specifically an undesirably large torsional force is required to close the fuel tank cap. Moreover, the torsional force is generally not uniform over the whole gasket, which interferes with desired enhancements of the sealing properties.
Another problem is that a fuel supply nozzle may collide with the seat surface, which is sealed with the gasket, when the fuel supply nozzle is inserted through the inlet opening. Damage to the seat surface generally leads to reduced sealing properties.